Are cold air intakes really worth it?
 

Been debating on buying one here lately and have mixed feelings. I'm sure the horsepower gain will be minimal if any. Heard a few that love them and heard a few that hate them. Any comments, suggestions, etc. would be apprecited.

I don't have one myself but I also have been thinking about getting one. The biggest gripe I've heard is that some Air intakes will cause the 8 to have "idling" issues. I guess it idles too low with some air intakes while at a stop or something. The best one I've heard so far with no idling issues is Racing Beat's so you might want to check them out.

Racing Beat's intake actually IMPROVES idling, contrary to some 'other' well-known brands...

oh, and i love mine, just for the change in intake sound is worth it, not to mention the little extra kick it gets, both mentally and actually :D

I bought the Ram Air Duct and noticed a power increase when turning low rpms at high speeds (65+)

also might want to think about how some been getting better mpg with the revi... thats why i would consider it...

better mpg.. hrm.. i might just get it... does it screw the warranty?

well guess i'll just change it back to stock if something goes wrong.. heh

I think the HP gain from some intake is negative (K&N Typhoon)...and Racing Beat's only reference to a HP gain is due to the removal of one of the Mass Air Flow sensor screens. I think if you are spending ~$420.00 for an intake you should get more then 2HP. For that type of money you should get a RP High Flow Mid pipe and nab yourself closer to 8HP or get an aluminum flywheel.
http://www.racingbeat.com/FRmazda4.htm

Stock vs Racing Beat

REVi Intake Adds An Average 1.95 HP Over The Stock System - 2000-8900 RPM Range

Peak RPM Gains Over Stock - 3.5 HP @ 8300 RPM

Maximum Power Gain Over Stock - 5.8 HP @ 8900 RPM

the whole idea is to get fresh air from outside the engine bay into the motor, If you can get the cooler/dense air that is around the car into the motor, it will allow you to more effectivly burn the fuel and in some cases burn more fuel.

The idea is correct, colder air will give more power the problem is actualy getting the cold air to the motor, when you cruising at low speeds or sitting/idling the intake will heat soak, so you have to get the intake speed up (going into high rpm) to move enough air thru to cool down the intake tract/have the air not pick up to much heat from the engine.

Also, you have to consider just how cold the outside air is. Here in FL right now, the air temp outside is upper 80's/low 90's and the air close to the road (where the intakes are picking it up) is even hotter. Also the high humidity here affects power.

Come winter when the temps drop, if you could get a night that wasnt to damp you would feel a much bigger gains.

You cant bolt on a cold air intake when its 95* out with 100% humidity and expect HUGE gains, but durring the right conditions, when its 50* out and low humidity you will get nice gains in performance.

Also to get the best effect you have to reset the computer.

do u have a pic of your car i am always in orlando on trips ect. I always see sweet ass rx8s , just wondering if one of them might be yours.

What intake do you have?

Seems logical to install the intake and exhaust together, but is it really worth it losing the warranty for such small gains.

I am assuming that the exhaust won't void the warranty because it is at the end of the system, but the intake may be another story.

I would think that the intake won't void the warranty until something goes wrong. Anyone know Mazda's take on intakes out there?

it really is more about how the dealer feels about the parts, not mazda. Some dealers are cool with little issues, esp if its something like "my rear shocks are blown" and you have an intake.

From what Ive heard from mazda, as long as the exhaust is after the emissions control system (after the cat and all o2 sensors) and the intake is before the MAF and other sensors, its ok. The problem is more with the intake since they have you install the MAF in their pipe, or something, cause you had to unhook it and remount it, you could have damaged/altered it and caused _____ problem.

I dont have an intake on the car right now, but Im going Revi with the ram air.

ECLPS0 - I dont have anything done to the outside of my car, other than the yellow fogs, I will have the MS bumper and sides on in a week or so, my car is silver touring. The inside of my car has some mods, but again nothing major.

In about a year Ill have the kit, wheels and suspension done...then you might beable to call my RX8 'sweet ass' but right now its just a stocker.

there is a silver one with factory apperance package, wheels and exhaust that is in orlando.

^ that silver one i was talking about also has the MS wing I belive

The best I have found is a "green" filter in the stock air box remove the first screen in the box, and replace the VFAD with a RB Ram Air set up.

i'm considering getting the revi+ram air once my warranty is up. my question is to those who live in areas with a lot of precip. the ram air is essentially a cai right? is there a decent chance of water entering the intake and causeing hydrolock? right now i'm up in western washington and we see more than our fair share of rain for about 9/12 months and eventually will be moving to honolulu, where rain is less likely. are my concerns warranted or are the chances fairly remote?

i just ran through a 5" puddle last weekend, when it was pouring cats and dogs here in northern VA, the car did just fine :D

the water have to be all the way up to where the guppy mouth is to cause a problem, but by that point i think you'd have other problems to worry about ;)

I woudlnt worry to much about the hydro-lock issue :

1) it is pretty difficult to hydro-lock any motor, since water is more dense than air, it take more force to lift it up (against gravity) and pull it through the pipe all the way into the engine, esp enough of it to make combustion impossible and then cause hydro-lock. You would have to drive thru water deep enough to completly or near-completly submerge the opening (filter) of the intake, and at the same time be at high enough RPM to have enough force to pull the water up. Its not very likely to happen if your carefull. Your more likely to have the car run rough or stall out. So I woudlnt worry about it.

2) Hydro-lock isnt as bad on a rotary, it would be similar to flooding it (with fuel). Since the water can get out easyer than a piston motor (where it has to go up through a valve, vs out through a port on the bottom) In fact people have used water to 'steam clean' the inside or rotary motors. If you were to hydro-lock a rotary, you could crank the motor to get most of the water out, then would just treat it like a flooded engine, pour some oil in to replace what was washed away and let it dry out.

Also the RevI + Ram Air is pulling in air from over 1 foot off the ground, so if your driving through water that deep, youve got other problems. Really all that could happen is you pull in some rain, that is hardly enough water to hydro-lock the engine, it might be enough to soak the air filter and cause a rough running/stalling but i doubt it.

All in all I wouldnt worry.

cool, thanks.

it's been a while, but i remember watching a video on clubwrx.net of a wrx/sti charging through a mud puddle with a cai and hydrolocking. what a way to ruin a 30K automobile.

When I opened up my REVi to seal it and the duct together, I did notice residue of what was once a pool of water.

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/sealed-my-revi-ram-air-silicone-72392/

Judging from the size of the pool of water in the box, and the fact that I had only driven it home from school once in the rain. I do suspect that this car could begin drinking water. Espically if you drive on the highway while its raining, all those cars kicking up water spray, it all goes right in the box :(

But, keep in mind that even though water is collecting in the box, there would probably need to be at least a liter of water collected in order for it to begin being sipped by the engine. A liter of water sloshing around in the intake tube and vacuum offshoot and with the MAF right there is bound to stall the car before it actually gets in the engine.

I think i saw another set up for ram air besides RB. I don't recall what it was.

Thanks for all the help on this. I was actually thinking about the water issue but that question was answered. Gonna take a good look at the Revi intake now. I know there are others but since you guys keep talking about it i rekon i should go with it.

Its called Odula.

hydrolocking is pretty hard to do... however, gradual wear over time from the engine gulping up water droplets may be a real issue, not to mention hell on your air filter

Aem cia had it for over 3 months. drove through major huricane rain and thunder i have no issues except for burning ALot of oil which is not from the intake